I started with a pane of glass out of a used sliding glass door. The glass is about 6 foot by 3 foot and I made a box out of treated 2 x 6’s and ½” mdx plywood to fit. I insulated the box with 1" Poli-iso and taped to seal. I had some ¾” square wood that I built a frame then looped aluminum screen. I did not make precise loops only ones that will come close or contact the glass and stapled to the wooden frame. I have an old 110v 6" box fan that I am using now. Input and outputs are 4" aluminum dryer vent hose. I have a digital Thermometer controller instead of a snap switch, and it has shown panel temps as high as 162 degrees F.

Welcome dademac. Your topic has been moved to the 'Member Projects' section and the duplicate post removed. Just a reminder that your first few posts have to be reviewed before they're published and it can take an hour or two.

Mike__________________Both temperature rise and airflow are integral to comparing hot air collectors

Interesting build, haven't seen that before. You said "and it has shown panel temps as high as 162 degrees F." Is that the output air temp?, with the with the fan running? If so you may want to add a booster fan to get more BTU's out. The higher the temp gets in there the more BTU's you lose through the glass.__________________Gordy,Minnesota

I do have a question about the temp readings. I agree with Gordy about the high temps wasting heat. But I'm wondering about thermometer placement. If the fan is running, and the output temp is 85˚F, where is the thermometer inside the panel placed, as it seems awfully high compared to the output temp. With it being 125˚F inside the panel it seems like the inside thermometer is in a bad location, such as an area with low airflow. And this 125˚ air will be lost.

Normally temps are taken right where the air enters and exits the collector box, the duct openings, out of direct sun. For a turn-around collector such as yours, a probe at the turn might be useful as this is where a lot of heat will build up due to the air slowing at the turn.

Do you have any idea of the amount of air passing through 60+ layers of screen? I'm surprised at how many layers you have successfully moved air through.

Thank you for the info about placement of temp probes. The output is a thermometer about an inch from the fan. The inside probe is a few inches from the output but close to the glazing. I do not know the volume of air passing through the collector.

Yes, I saw the frame for the loops and it looks like it's on the ends too, and not just the sides. Even so, that's an awful lot of layers for air to pass through even if some air can simply bypass the screens by passing under them, or over them for that matter. Hard to get much airflow without larger ducts and more powerful fan.

You are right the screens sit 3/4" off of the back and I never considered about how much air is passing under the screens. I did tape them down but not to the point of making all the air go through. I guess that will part of revision 1.

Easy fix would be some 1/2 Polyiso cut to fit in the screen frame, and fixed against the screen.

Don't take any of this as criticism of what you built. We want to help you get the most out of it. And I applaud you for actually building something and making heat, you have done so much more than most ever get around to. Many think its a good idea and talk about building something but never do.__________________Gordy,Minnesota

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